Create 3069-distribute-elements-into-two-arrays-i.java

Author: sanajitjana

Easy/3069-distribute-elements-into-two-arrays-i.java

@@ -0,0 +1,64 @@
+/*
+ * Title: 3002. Result Array After Splitting
+ * Link: https://leetcode.com/problems/result-array-after-splitting/
+ *
+ * Problem:
+ * You are given an integer array nums. 
+ * You must split it into two arrays list1 and list2 such that:
+ *  - list1 starts with nums[0]
+ *  - list2 starts with nums[1]
+ *  - For every i from 2 to n-1, compare the last elements of list1 and list2:
+ *      -> If last element of list1 > last element of list2, put nums[i] in list1
+ *      -> Otherwise, put nums[i] in list2
+ * Finally, return the concatenation of list1 followed by list2.
+ *
+ * Approach:
+ * - Initialize list1 with nums[0] and list2 with nums[1].
+ * - Traverse nums from index 2.
+ * - At each step, compare the last element of list1 and list2.
+ * - Place nums[i] into the list whose last element is greater (list1) or smaller (list2).
+ * - After traversal, build the final result array by appending list1 followed by list2.
+ *
+ * Dry Run:
+ * Example: nums = [2, 1, 3, 3]
+ *   list1 = [2], list2 = [1]
+ *   i=2 → compare lastList1=2, lastList2=1 → list1 wins → list1=[2,3]
+ *   i=3 → compare lastList1=3, lastList2=1 → list1 wins → list1=[2,3,3]
+ * Final result = [2,3,3,1]
+ *
+ * Time Complexity: O(n) → single pass over nums, building result in linear time
+ * Space Complexity: O(n) → extra space used for list1 and list2
+ */
+
+class Solution {
+    public int[] resultArray(int[] nums) {
+        int length = nums.length;
+
+        List<Integer> list1 = new ArrayList<>();
+        List<Integer> list2 = new ArrayList<>();
+
+        list1.add(nums[0]);
+        list2.add(nums[1]);
+
+        for (int i = 2; i < length; i++) {
+            int lastList1 = list1.get(list1.size() - 1);
+            int lastList2 = list2.get(list2.size() - 1);
+
+            if (lastList1 > lastList2) {
+                list1.add(nums[i]);
+            } else {
+                list2.add(nums[i]);
+            }
+        }
+
+        int[] ans = new int[length];
+        int index = 0;
+        for (int ele : list1) {
+            ans[index++] = ele;
+        }
+        for (int ele : list2) {
+            ans[index++] = ele;
+        }
+        return ans;
+    }
+}